Conventionally, a refrigeration cycle device is known which includes an ejector serving as refrigerant decompression means and refrigerant circulation means. The refrigeration cycle device having the ejector is effectively used, for example, for an air conditioner for a vehicle, a refrigeration device for freezing and refrigerating goods mounted on a vehicle, or the like. Further, the refrigeration cycle device is also effectively used as a stationary refrigerant cycle system, for example, an air conditioner, a refrigerator, a freezer, and the like.
JP-A-2007-57222 (corresponding to WO 2006/109617 A1) proposes such a refrigeration cycle device. In this document, an ejector is formed integrally with an evaporator. Thus, the ejector and the evaporator can be handled as one integrated unit, thereby improving the mounting property of the refrigeration cycle device on a vehicle.
Specifically, as shown in FIG. 12, a first evaporator 15 and a second evaporator 18 are assembled to an integrated structure, and an ejector 14 is incorporated in a tank 18b of the second evaporator 18.
The ejector 14 draws refrigerant from a refrigerant suction port 14b by a refrigerant flow injected from a nozzle portion, and mixes the refrigerant injected from the nozzle portion with the refrigerant drawn from the refrigerant suction port 14b to discharge the mixed refrigerant from a diffuser.
The ejector 14 has an elongated shape with a refrigerant flow inlet 14e of the nozzle portion located on one end side thereof in the longitudinal direction (on the left end side shown in FIG. 12), and a refrigerant discharge port 14f of the diffuser located on the other end side thereof in the longitudinal direction (on the right end shown in FIG. 12). The refrigerant suction port 14b is located between the refrigerant flow inlet 14e and the refrigerant discharge port 14f in the longitudinal direction of the ejector 14.
The refrigerant suction port 14b of the ejector 14 is opened to a collection space 27 for collecting the refrigerant flowing from a plurality of tubes (not shown) in the tank 18b of the second evaporator 18. The refrigerant in the collection space 27 is drawn into the ejector 14 from the refrigerant suction port 14b. 
A first O-ring (elastic member) 29a is provided for preventing the refrigerant discharged from the refrigerant discharge port 14f of the diffuser from leaking into the collection space 27 as shown by the arrow X with the broken line in FIG. 12. A second O-ring (elastic member) 29b is provided for preventing the refrigerant flowing into the refrigerant flow inlet 14e of the nozzle portion from leaking into the collection space 27 as shown by the arrow Y with the broken line in FIG. 12.
With this arrangement, the ejector 14 can be fixed in the longitudinal direction by using screw fixing means.
However, according to the detailed studies by the inventors of the present application, incorporating the ejector 14 in the tank 18b of the second evaporator 18 may generate abnormal noise from the evaporator 18.
That is, since the ejector 14 serves as refrigerant decompression means, vibration occurs from the ejector 14 due to disturbance of the refrigerant flow in decompression of the refrigerant. The ejector 14 is incorporated and fixed in and to the tank 18b of the evaporator 18 by screws, which allows the vibration of the ejector 14 to be easily transmitted to the tank 18b. 
Thus, the vibration generated from the ejector 14 may be transmitted to the entire evaporator 18 itself, resulting in radiated sound (abnormal noise) from the evaporator 18.
The inventors of the present application have studied about prevention of the transmission of vibration from the ejector 14 to the tank 18b by effectively using vibration isolation capability of the O-rings 29a and 29b, taking into consideration the contact between the ejector 14 and the tank 18b via the O-rings (elastic members) 29a and 29b and the vibration isolation capability of the general elastic member.
The vibration isolation capability of the O-rings 29a and 29b, however, is contradictory to seal capability inherent to the O-rings 29a and 29b. That is, in order for the O-rings 29a and 29b to have sufficient vibration isolation capability, it is only necessary to decrease the hardness of each of the O-rings 29a and 29b, thereby improving a buffer effect thereof. In contrast, the decrease in hardness of the O-rings 29a and 29b leads to degradation of adhesion and further of the seal capability.
For this reason, simply by decreasing the hardness of the O-rings 29a and 29b, the vibration isolation capability of each of the O-rings 29a and 29b may be improved, but the seal capability thereof cannot be assured. Thus, it may cause a leak of the refrigerant as indicated by the arrow X or Y with the broken line in FIG. 12.